Fair Value Measurements and Marketable Securities - Available-For-Sale Securities Reconciliation (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities
Amortized Cost	$ 11,960	$ 11,960
Unrealized Gain	0	0
Unrealized Loss	(2)	(8)
Estimated Fair Value	11,958us-gaap_AvailableForSaleSecurities	11,952us-gaap_AvailableForSaleSecurities
Certificates of Deposit [Member]
Schedule of Available-for-sale Securities
Amortized Cost	11,960	11,960
Unrealized Gain	0	0
Unrealized Loss	(2)	(8)
Estimated Fair Value	$ 11,958	$ 11,952

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

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Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

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This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

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